The government has not ruled out sabotage as a cause of India's massive power transmission failures last week that left around 700 million people without electricity, and has initiated an investigation by the Intelligence Bureau (IB) , CERT-In (Indian Computer Emergency Response Team) and the National Technical Research Organisation (NTRO).

While IB is investigating whether sabotage was one of the causes of the worst grid failures that India has experienced, NTRO is looking at possible cyber attacks being behind the blackouts.

"The investigations are being carried out by IB and NTRO. This is being done to get at the root of the problem and they are not discarding any possibilities," said a senior government official requesting anonymity due to the sensitive nature of the issue.

"After the grid failure, there was lot of speculation that it is a Chinese attack. CERT-In (Indian Computer Emergency Response Team) then inquired about the incident from Power Grid and NTPC. Both reported that it was a case only of overloading and they did not allow their equipment to be screened. IB also found out that there is no prior or past intelligence of any wrongdoing about grid failure," said another government official aware of the development, who also didn't want to be identified.

While CERT-In is tasked with responding to cyber attacks, NTRO is the country's elite technical intelligence agency.

Load management functions are overseen by state-owned Power Grid Corp. of India Ltd (PGCIL) and carried out by its subsidiary Power System Operation Corp. Ltd.

There have been concerns earlier that the country's power infrastructure could be the next target of terrorists looking to cripple India's economy. IB had warned the power ministry in early 2009 that substations and regional load despatch centres (RLDCs), both key components in the country's power network, could be targeted. Substations are an important part of the electricity network and play a critical role in the generation, transmission and distribution system. They increase or decrease electricity voltage for transmission and distribution purposes.

A committee headed by A.S. Bakshi, chairman of the Central Electricity Authority, has been formed to inquire into the reasons for the collapse last week. Stung by criticism in the wake of grid failures, northern states such as Delhi, Uttar Pradesh, Punjab, Haryana, Rajasthan, Uttarakhand, Himachal Pradesh and Jammu and Kashmir plan to set up defence mechanisms such as islanding for specific regions and critical infrastructure such as airports, railways and water supply, among others. This would isolate a disturbance on the national power grid, restricting it to a particular region, or allow a particular region or essential service to isolate itself in the event of a grid failure.

Consultancy firm Frost and Sullivan described the collapse as "one of the world's most widespread power failures, bringing normal life to a standstill". It added, "As an aftermath of the outage, normal life in the entire northern region was crippled, including transportation facilities."

A grid collapse is the worst-case scenario for any transmission utility; if this happens, states that draw power from that particular network go without power. India has five regional grids—northern, southern, eastern, north-eastern and western. All except the southern one are connected.

RLDCs, which fall under the purview of PGCIL, are responsible for maintaining grid discipline, and supervising optimum scheduling and delivery of electricity in their regions. The country has 33 state load despatch centres, five RLDCs, and one national load despatch centre. The 155 major substations that are responsible for the flow of power across state borders come under PGCIL, which manages power transmission across the country, and owns and operates around 95,009 circuit km of transmission lines.